Former Irish president Mary Robinson has revealed she was on the verge of a breakdown when she took one of the top posts in the United Nations.

In a revealing and intimate interview on BBC Radio 4, she also confessed her problems with the Catholic Church over its authoritarian stance on family planning.

Ms Robinson, who quit her presidency three months before her end of term in 1997 to take up the job as UN High Commissioner for Human Rights, said she struggled with stress.

"I decided to get up earlier in the morning, come in, work harder, work later," she said. "I started taking sleeping pills and by the first Christmas in 1997 I was a wreck. I was exhausted.

"My eldest brother who was a doctor took a look at me and he told me, 'Mary, you've got to watch it, you're going into breakdown territory'."

The 69-year-old said she ultimately decided to throw away her sleeping pills and take a break. "I took an extra week and spent a lot of time walking by the lake and pulled myself together," she said. "I decided I've got to get on top of this. I've got to do this job."

Ms Robinson became emotional during an airing of the famous Desert Island Discs. She broke into tears as she recalled a trip to Delhi, when a crowd of children gave a rousing performance of We Shall Overcome - a song she chose as one of her desert island discs.

Ms Robinson, who was Ireland's first female president as well as the first to meet the Queen at Buckingham Palace, also discussed her faith.

"I'm not somebody who goes to mass every Sunday because I feel I have to," she said. "I'm deeply spiritual and I'm seeking to understand the way in which so much of the Catholic Church is so authoritarian not supporting family planning. So there's a great deal that I'm very, very troubled by."

She said she still believes in the "gospel of Jesus as being the highest standard that we can attain".